1. Field of the Invention
The invention relates to an intervertebral cage that can be inserted between upper and lower vertebrae in longitudinal and slating directions after an intervertebral disk is removed.
2. Description of the Related Art
There have been known intervertebral cages inserted between the vertebrae the intervertebral disk of which is removed.
FIGS. 1 and 2 show an intervertebral cage of a related art of this invention (Japanese Unexamined Patent Publication No. 9-503416). In the related art, an intervertebral cage 50 is comprised of a pair of left and right semicircular lateral spacers 51A, 51B; front and rear central spacers 53A, 53B are integrally fixed to each other by left and right fixing screws 55. This intervertebral cage 50 is inserted between upper and lower vertebrae 59U, 59L after an intervertebral disk is removed. The central spacers 53A, 53B and lateral spacers 51A, 51B define a cavity 70.
The related art has a problem that 1) since the intervertebral cage 50 is comprised of a large number of components and has a complex structure, and 2) does not have protrusions for preventing itself from coming off, it can not sufficiently be fixed between the vertebrae after it is inserted between the vertebrae.
Further, in the related art, it is premised that the intervertebral cage 50 is inserted between the upper and lower vertebrae from an anterior side but is not inserted from longitudinal and slanting anterior sides. Thus, an improved intervertebral cage has been desired.